Three-dimensional (3-D) curves are used to create a wide range of digital content including digital images, digital movies, and the like. Modelling 3-D curves using conventional systems, however, is hard and tedious and typically requires multiple viewpoints and iterations. Specifically, conventional systems require a designer to generate 3-D content on a 2-dimensional (2-D) screen using a mouse or a stylus. In this instance, there is a 2-D view inside of a 3-D environment. Accordingly, if the designer wishes to draw or sketch some curves from a single viewpoint it becomes non-trivial to enable the designer to do so. This is because the designer has a 2-D input device on a 2-D flat display on which they are attempting to draw a 3-D curve. What occurs in many conventional modeling systems today is that in order to draw a 3-D curve, the model constantly has to iteratively rotate to provide multiple viewpoints. So, for example, the designer may draw a first portion of a curve and then the model will have to rotate to show the next portion of the model to enable the designer to draw the next portion of the curve. This process typically happens over and over. That is, the designer will draw a curve portion, the model will rotate, the designer will draw a next curve portion, the model will rotate, and so on. This process can be very slow and tiring for the designer.